SPOKANE, Wash. - The question of how free speech applies to the side of buses is before a panel of federal judges. Members of the 9th Circuit Court of Appeals heard oral arguments Wednesday in a special meeting in Spokane. The case stems from a controversial ad on Seattle buses but has implications for transit systems around the Northwest.

A group called the Seattle Mideast Awareness Campaign bought the ad in 2010. It shows children standing next to the rubble of a destroyed building. The text says, “Israeli War Crimes: Your Tax Dollars At Work.”

The King County transit agency pulled the ad after complaints and because of worries it might lead to vandalism or violence.

But the Mideast Awareness Campaign argues the county violated its free speech rights. In court, the judges wondered at what point the county has a right avoid disruption. After all, said the chief judge, it’s “a bus system, not a sign company.”

To the county, the judges turned that around, asking if vehement public reaction is enough to take down an ad -– and if that wouldn’t be an invitation to people who want to quash opinions they don’t like.

The panel also questioned both sides about whether Seattle buses are even a public forum to begin with.